public void setPosition(Vector p) {
   position.x = p.x;
   position.y = p.y;
 }
 public void setPosition(double x, double y) {
   position.x = x;
   position.y = y;
 }
 public Vector getPosition(Vector p) {
   position.x = p.x;
   position.y = p.y;
   return position;
 }